This invention relates to a stamp making device which makes a printing plate from a porous resin member.
As disclosed in U.S. Pat. No. 5,644,136, a conventional stamp making device includes an irradiation unit that applies ultraviolet rays to a resin member which is sensitive to ultraviolet rays. The stamp making device further includes an original printing unit that prints an image on a film by means of a thermal head, thereby to make an original film having a desired image. The original film is provided between the resin member and the irradiation unit. Irradiated portions of the resin member are cured, while non-irradiated portions of the resin member are not cured. The non-irradiated (non-cured) portions of the resin member are removed by a washing process, so that the irradiated (cured) portions remain on the resin member as projections.
However, such a conventional stamp making device has a disadvantage such that the operation is complicated, since the washing process is necessary. Further, in order to avoid unintentional irradiation of the resin member, the resin member should be stored in a lightproof case.
Further, there is a possibility that an user mistakenly operates the stamp making device without setting the original film thereon. In such a case, a waste printing plate may be made. Thus, there is a strong demand for a stamp making device in which an operation under insufficient condition is prohibited.
It is therefore an object of the present invention to provide a stamp making device wherein a stamp making process is simple.
Further, it is another object of the present invention to provide a stamp making device in which an operation under insufficient condition is prohibited.
According to one aspect of the present invention, there is provided a stamp making device including (1) a data input unit into which image data is inputted, (2) an original printing unit including a thermal head and a platen which nip a transparent film and an ink ribbon therebetween, the thermal head being driven to print an image on the transparent film based on the image data, thereby to make an original film, (3) an irradiation unit including a transparent support plate and a light source, (4) an original feeder which feeds the original film to the transparent support plate, and (5) a biasing unit which biases the porous resin member to the original film on the transparent support plate. The irradiation unit applies light to the porous resin member through the original film, in a state the biasing unit biases the porous resin member to the original film, so that an irradiated portion of the porous resin member is melted.
With such an arrangement, an irradiated portion of the porous resin member is melted and solidified, while non-irradiated portion of the porous resin member remains elastic. When the biasing force is removed, the non-irradiated portion of the porous resin member recovers its original thickness, while the irradiated (solidified) portion of the porous resin member remains the same as it is biased. Thus, the non-irradiated portion of the porous resin member becomes a projection. Stamp ink impregnated in the printing plate is transferred to a recording media through the projection of the printing plate.
As constructed above, since the washing process is not necessary, the stamp making operation becomes simple. Further, since it is not necessary to store the porous resin member in a lightproof case, the porous resin member can be handled in a simple manner. Furthermore, since the stamp pattern is made according to the inputted image data, a wide variety of stamp pattern can be formed.
Particularly, the original film is laid on the transparent support plate so that a printed surface of the original film is faced with the porous resin member. With this, the image on the original film is so-called a positive image. Thus, the original printing unit is able to print the image on the original film in a similar manner that a thermal printer prints an image on a paper.
In a preferred embodiment, a width of the transparent film is greater than a width of the ink ribbon. The original printing unit further includes a feeding roller pair which nip the transparent film and the ink ribbon therebetween. One of the feeding roller pair (located at the ink ribbon side) has projections which grip both of the ink ribbon and the transparent film. Thus, the positioning error of the transparent film and the ink ribbon is prevented. Accordingly, the blurring of the printed image on the original film is prevented.
It is preferred to provide a guiding structure which guides both sides of the original film, from the original printing unit to the irradiation unit. Thus, the original film can be correctly positioned on the transparent support plate of the irradiation unit.
In a particular arrangement, the stamp making device further includes (1) a cut sheet introducing unit which introduces the cut sheet between the transparent film and the ink ribbon, and (2) a cut sheet detector which detects if the cut sheet reaches a predetermined portion where the thermal head is able to print an image on the cut sheet. When the cut sheet detector detects the cut sheet reaching the predetermined portion, the thermal head prints the image on the cut sheet. After the image is printed on the cut sheet, the cut sheet is separated from the ink ribbon and the transparent film, and discharged out of the stamp making device.
With such an arrangement, a label (having the same pattern as the printing plate) can be easily made. The label is attached on a top portion of the stamp, so that a user can easily recognize the pattern of the stamp.
Preferably, the cut sheet introducing unit feeds the cut sheet at a lower speed compared with a feeding speed of the transparent film and the ink ribbon. Thus, tension is applied on the cut sheet. In one case, it is possible to provide a separating unit which separates the cut sheet from the ink ribbon and the transparent film. Preferably, a separation angle of the cut sheet from each of the ink ribbon and the transparent film is not less than 45 degrees.
In another preferred embodiment, the stamp making device further includes (1) a body including fixed and openable frames opposing with each other, the openable frame being swingable, (2) a ribbon cassette accommodating the ink ribbon, (3) a film cassette accommodating the transparent film, (4) a ribbon cassette mounting portion provided in the body, which has at least one shaft extending from the fixed frame toward the openable frame, and (5) a film cassette mounting portion provided in the body, which has at least one shaft extending from the fixed frame toward the openable frame. When the openable frame is closed, each of the shafts of the mounting portions is supported at both ends thereof by the fixed and openable frames.
With such an arrangement, the cassettes can be easily mounted to and detached from the stamp making device, by opening the openable frame and by pushing/pulling the cassettes along the shafts.
It is preferred to further provide (1) an arrangement which moves the platen toward and away from the thermal head thereby to nip and release the ink ribbon and the transparent film, and (2) a lock mechanism which locks the openable frame to prohibit the openable frame from opening when the platen is toward the thermal head.
In another preferred embodiment, the stamp making device further includes (1) a first detector which detects if the original film is set on the irradiation unit, (2) a second detector which detects if the porous resin member is set on the irradiation unit, (3) a third detector which detects if the porous resin member is biased, and (4) an irradiation prohibit unit which prohibits the irradiation of the light source, when a negative result is obtained from any of the detectors. Therefore, an operation under insufficient condition (for example, when the stamp is not mounted) is prevented.
Optionally, the light source is a xenon tube. In such a case, it is preferred that the irradiation prohibit unit prohibits the irradiation when charging of the xenon tube is not completed. Further, the irradiation unit includes a cover which prevents a leakage of light. The irradiation prohibit unit prohibits the irradiation of the light source when a cover is not closed. With this, a user is protected from the light.
It is preferable to further provide a stamp size detector which detects a size of the stamp mounted on the stamp making device. The stamp size detector determines if the stamp size is suitable for the original film. Thus, when a porous resin member is too small (or large) compared with the original film, the operation of the stamp making device is prevented. Thus, a waste printing plate is not generated.
In another particular arrangement, a transparent sheet is provided between the porous resin member and the printed image of the original film. The thickness of the transparent sheet is not less than 0.019 mm.
In the stamp making device, the original film is laid on a transparent support plate made of acrylic resin or the like. When the printed image of the original film is heated, the heat may be transmitted to the support plate.
However, since the transparent sheet (not less than 0.019 mm in thickness) exists between the transparent support plate and the printed image, the heat of the printed image is diffused in the transparent sheet. Thus, the heat damage to the transparent support plate is prevented. Advantageously, the thickness of the transparent sheet is not less than 0.025 mm.
It is preferable that the original film is made of a transparent film not less than 0.019 mm in thickness with a black image being printed thereon. The original film is laid on the transparent support plate so that the printed image is faced with the porous resin member. With this, the transparent film of the original film acts as the above-described transparent sheet. Thus, the heat damage of the transparent support plate is prevented, without providing a separate transparent sheet. Advantageously, the thickness of the transparent film of the original film is not less than 0.025 mm.
Further, the transparent support plate is made of acrylic plastic. The transparent sheet is made of polyethylene terephthalate. Since the melting point of polyethylene terephthalate is higher than the melting point of the porous resin, the transparent sheet itself is not damaged by heat.
In one case, the porous resin member is made of polyurethane resin including 0.1 to 15 wt % carbon black. The light source is a xenon tube which is strong enough to melt the porous resin member. With this, an irradiated portion of the porous resin member is melted and solidified. Although the printed image (ink image) on the original film is also heated by the irradiation of the xenon tube, the heat of printed image is diffused in the transparent film. Thus, the heat damage to the transparent support plate is prevented. The xenon tube has an advantage such that the irradiation energy can be easily adjusted. Further, different from a flash bulb, it is not necessary to replace the xenon tube at every irradiation.